Nice article and very applicable to CMANO
Key points (borrowed and modified from J Solomon's ID article
Defeat Submarines in Port and their supporting infrastructure
Defeat their Command and Control
Defeat submarines outbound from port or in confined spaces
Destroy submarines choke points they must pass through.
Draw submarines into kill boxes
Mask forces from submarine detection
Defeat subs in close battle
Defeat the incoming torpedo or missile
Create conditions where enemy won't employ submarines.